This invention relates generally to flexible packages, and more particularly to flexible packages for holding flowable products suitable for use in clean environments.
Various types of flexible packages for holding particulate materials, e.g., foodstuffs, chemicals, etc., under vacuum have been disclosed in the patent literature and are commercially available today. One type of flexible package is commonly constructed in the form of a "bag," or "pouch," or "sack" having a front panel and a rear panel secured together along their marginal edges so that when it is filled it has the shape of a somewhat flattened pillow. In order to gain access to the product within the pouch, a mouth is typically provided adjacent the top end of the pouch. The mouth may be constructed so that the front and rear panels forming the pouch are releasably connected to each other, e.g., can be peeled apart, to enable the panels of the pouch to be grasped to open the mouth of the package. Alternatively, the mouth of the package can be made severable, e.g., it may be arranged such that it can be cut or torn along a predetermined line to provide access to the interior of the package.
For some industrial or food processing applications, flowable materials, e.g., powders, granular materials, etc., that need to be processed in a clean or sanitary environment to produce a final product are temporarily packaged to keep them clean or sanitary until they are ready for processing. Conventional containers, such as flexible packages, have left much to be desired for such temporary packaging applications, since such packages are susceptible to becoming soiled or otherwise contaminated during transportation and/or handling. Thus, flowable materials which are packaged in conventional flexible packages, typically will have to be taken out of the packages in which they were shipped/handled and placed in secondary (clean) packages or containers before being introduced into the clean environment for processing. Obviously, such action is wasteful of time and resources.
So called "two stage" packages have been provided in the prior art. Such packages make use of an inner wrapper in which the product to be processed is packaged. The inner wrapper is then placed in a second wrapper for shipping and handling to keep the innerwrapper's surface clean or otherwise uncontaminated during such shipping/handling. One example of such a prior art two stage package is shown in U.S. Pat. No. 5,149,315 (Muhs). That patent discloses a bag construction comprising an outer bag and an inner bag contained therein and a method of making the structure. The bag has an independent unitary construction and is made from a tube length having inner and outer portions, by cross sealing the inner portion and folding the outer portion into a rectangularly shaped bottom. The bottom of the bag is sealed to resist leakage so that the contents of the bag will be maintained in good condition without loss or deterioration by reason of sifting or breathing through breaks or openings in the bottom seal. The inner bag is leakproof and is adhered to the outer bag in a manner such that the inner bag can be removed easily from the outer bag for disposal purposes.
While the aforementioned prior art is generally suitable for its intended purposes, a need still presently exists for a flexible package for holding flowable materials that is to be kept sanitary and/or uncontaminated even when the package is handled and/or transported under conditions that would tend to soil or contaminate the exterior of the package, yet which can be converted into a clean state, suitable for introduction into a clean environment where the material within the package can be safely removed.
Accordingly, a need presently exists for a flexible package for holding flowable materials that is to be kept sanitary and/or uncontaminated even when the package is handled and/or transported under conditions that would tend to soil or contaminate the exterior of the package, yet which can be converted into a clean state, suitable for introduction into a clean environment where the material within the package can be safely removed.